Dental Filling, Dental restoration

The materials most frequently used for direct dental restoration are amalgam, composite resin (plastic and glass), glass ionomer cement (glass + organic acid) and resin ionomer cement (resin + glass + organic acid). For indirect dental restoration (inlays, crowns, bridges and frameworks), ceramic porcelain, metal-fused porcelain, gold and copper alloys, and nickel, cobalt and chromium alloys are used. Resins are biocompatible and safe. Glass cements and other dental materials (porcelain, gold, nickel, cobalt and chromium alloys) are non-toxic and safe. ^{(Dental Board 2005)}

Amalgams contain mercury (Hg), silver, tin and copper. Hg vapours are continuously released from fillings, especially when chewing (particularly chewing gum) and drinking very hot liquids, increasing Hg concentrations in plasma and in the milk of nursing mothers.

There is controversy over the amount of mercury from amalgams that passes into the blood and breast milk and its clinical repercussions on infants:

• Some authors believe it to be excessive ^{(Gul 2016)} and that daily Hg intake exceeds the FAO/WHO recommendation. ^{(Norouzi 2012, da Costa 2005)}
• Other authors believe it to be very small, much lower than that which passes through eating fish and much lower than that which passes through the placenta during pregnancy, such that the levels of Hg found in cord blood progressively decrease in infants, whether breastfed or not, in the first few weeks. ^{(Drexler 1998, Drasch 1998)}
• There are no proven clinical repercussions. ^{(Rebelo 2017, Al-Saleh 2015, Vieira 2013, Jiménez 2013 Barghi 2012, Norouzi 2012, Richardson 2011, Roberts 2009, FDA 2009, da Costa 2005, Ursinyova 2005, Ekstrand 1998, Drexler 1998, Klemann 1990)}
• There is no scientific basis for attributing any disease to amalgam fillings. ^{(FDA 2009, Mitchell 2005, Brownawell 2005, Ekstrand 1998)}

Having amalgam dental fillings is not a contraindication for breastfeeding. (Drasch 1998)

It is not advisable to place or remove amalgam fillings during pregnancy and breastfeeding or, if necessary, to do so with appropriate precautions, as mercury vapours are released and inhaled ^{(FDA 2021 & 2015, Ekstrand 1998)} and pass into the blood and milk.

In some northern European countries and in the USA, informed consent regarding the dental filling material to be used is mandatory. ^{(Edlich 2007)}

The WHO's objective is to reduce and eliminate all exposure to mercury worldwide. Dental amalgams fall within this phase-out policy: although an amalgam filling that does not cause problems should be left in place, for the next filling, the use of resin or cement should be considered. ^{(WHO 2017)}

See below the information of this related product:

• Mercury (Unsafe. Moderate/severe adverse effects. Compatible under certain circumstances. Follow-up recommended. Use safer alternative or discontinue breastfeeding from 5 to 7 T ½ . Read Commentary.)